This disclosure relates to a fuel vapor recovery apparatus including an adsorbent canister capable of capturing fuel vapor produced in a fuel tank, a purge passage connecting the adsorbent canister to an intake passage of an internal combustion engine, and a purge pump for delivering the fuel vapor from the adsorbent canister to the intake passage via the purge passage.
Referring to FIG. 1, Japanese Laid-Open Patent Publication No. 2007-177728 discloses a conventional fuel vapor recovery apparatus including an adsorbent canister 100, a vapor passage 104 communicating the adsorbent canister 100 with a fuel tank 103, a purge passage 106 communicating the adsorbent canister 100 with an intake passage 110 of an engine, and an atmospheric passage 107 for introducing the atmospheric air into the adsorbent canister 100. The adsorbent canister 100 is filled with an adsorbent 101 such as activated carbon, which is capable of removably adsorbing fuel vapor. The purge passage 106 is provided with a purge valve 106v and a purge pump 106p. The purge valve 106v is opened and closed for controlling fluid communication through the purge passage 106. The atmospheric passage 107 is provided with an atmospheric valve 107v for controlling fluid communication through the atmospheric passage 107. When the purge valve 106v of the purge passage 106 and the atmospheric valve 107v of the atmospheric passage 107 are closed, the fuel vapor flows through the vapor passage 104 from the fuel tank 103 to the adsorbent canister 100 and is adsorbed on the adsorbent 101. When the purge valve 106v of the purge passage 106 and the atmospheric valve 107v of the atmospheric passage 107 are opened and the purge pump 106p is driven, the adsorbent canister 100 is purged with the atmospheric air so as to desorb the fuel vapor from the adsorbent 101. Then, the air and the fuel vapor are introduced into the intake passage 110 of the engine.
The fuel vapor recovery apparatus of Japanese Laid-Open Patent Publication No. 2007-177728 has the purge pump 106p provided at the purge passage 106. Generally, the purge pump 106p is located near the intake passage 110 of the engine and is placed in an engine room of a vehicle. Whereas, the adsorbent canister 100 is located near the fuel tank 103 and is placed below a floor of the vehicle or the like. Because the adsorbent canister 100 is distant from the purge pump 106p, the fuel vapor cools and may become liquid while flowing through the purge passage 106 from the adsorbent canister 100 to the purge pump 106p. Thus, there is a possibility that liquid fuel liquefied from the fuel vapor in the purge passage 106 flows into a pump part of the purge pump 106p, and then intrudes into a motor part configured to drive the pump part. The intrusion of the liquid fuel into the motor part may cause failure of the purge pump 106p. Therefore, there has been a need for an improved fuel vapor recovery apparatus.